KR20120117010A - Epoxidation of an olefin - Google Patents

Abstract

The present invention provides one or more aspects of the process for epoxidation of olefins. For this embodiment, the method comprises reacting the olefin (where the olefin is not propylene) and a hydrogen peroxide solution at a predetermined pH at the desired reaction temperature in the presence of a catalyst and a solvent. The pH of the hydrogen peroxide solution is adjusted to the desired pH by contacting the hydrogen peroxide solution with a supported base to remove acidic species from the hydrogen peroxide solution.

Description

Epoxylation of Olefin {EPOXIDATION OF AN OLEFIN}

The present invention relates to a process for preparing epoxides by epoxidizing olefins.

Epoxides are prepared by a variety of techniques. One commercial technique for preparing epoxides involves reacting olefins with hydrogen peroxide and one or more catalysts in a protic medium. However, epoxidation of olefins in protic media can reduce the selectivity of the epoxidation reaction. In addition to the decrease in selectivity, the amount of by-products formed during epoxidation may increase as the epoxide reacts with the protic medium and as the epoxide oligomerizes and / or polymerizes. This reduction in selectivity also increases the manufacturing cost due to the low yield of epoxide and the steps necessary to separate the byproduct from the epoxide.

Accordingly, efforts are being made to increase the selectivity of the epoxidation process. This effort involves using a pretreated catalyst and homogeneous organic or inorganic compounds to change the pH of the reaction mixture. However, although the selectivity of the epoxidation reaction can be increased in these prior methods, the hydrogen peroxide utilization, the hydrogen peroxide conversion and the lifetime of the catalyst can simultaneously decrease. These drawbacks reduce manufacturing efficiency by producing less epoxide compared to the amount of material used.

summary

The present invention provides one or more aspects of the process for epoxidation of olefins. For this embodiment, the epoxidation of the olefins comprises reacting the olefins (where the olefins are not propylene) and a hydrogen peroxide solution at a predetermined pH at the desired reaction temperature in the presence of a catalyst and a solvent. The pH of the hydrogen peroxide solution is adjusted to the desired pH by contacting the hydrogen peroxide solution with a supported base to remove acidic species from the hydrogen peroxide solution. For this embodiment, the selectivity of epoxidation of the olefins does not reduce hydrogen peroxide utilization or hydrogen peroxide conversion compared to epoxidation of olefins without using a supported base to adjust the pH of the hydrogen peroxide solution to the desired pH. Without being increased. The present invention also provides epoxides obtained by the methods described herein.

Embodiments of the present invention also include methods of preparing epichlorohydrin. For this embodiment, the process for preparing epichlorohydrin comprises reacting allyl chloride with a hydrogen peroxide solution at a predetermined pH in the presence of a catalyst and a solvent. The pH of the hydrogen peroxide solution is adjusted to the desired pH by contacting the hydrogen peroxide solution with a supported base to remove acidic species from the hydrogen peroxide solution. For this embodiment, the selectivity of epoxidation of allyl chloride can be used to determine the hydrogen peroxide availability or hydrogen peroxide conversion compared to the epoxidation of allyl chloride without using a supported base to adjust the pH of the hydrogen peroxide solution to the desired pH. It is increased without decreasing.

1 shows the amount of epichlorohydrin formed during epoxidation of allyl chloride.

Justice

"Epoxide" refers to a compound in which an oxygen atom is directly attached to two adjacent or non-adjacent carbon atoms of a carbon chain or ring system. Epichlorohydrin (epi) is an example of an epoxide and is formed from the epoxidation of allyl chloride.

“Selectivity” refers to the amount of epoxide formed, based on the amount of epoxide formed plus all byproducts.

"By by-product" refers to all materials formed from epoxidation of olefins-epoxides. For example, in the case of epoxidation of allyl chloride, the byproducts may include water, 1-chloro-3-methoxy-2-propanol (CMP), monochlorohydrin (MCH) and high molecular weight byproducts.

"High molecular weight byproduct" refers to a byproduct formed from the epoxidation of allyl chloride that elutes after MCH during gas chromatography.

"Hydrogen peroxide conversion" refers to the amount of hydrogen peroxide reacted during epoxidation of olefins based on the amount of hydrogen peroxide added to the reaction mixture.

“Hydrogen peroxide utilization” refers to the amount of hydrogen peroxide converted to epoxide based on the amount of hydrogen peroxide reacted during olefin epoxidation.

"Supported base" refers to a non-soluble support having a basic functional group with a neutral charge.

"Neutral charge" refers to a material that has no ions such that the material has neither positive charge nor negative charge.

"Stabilizer" refers to a material, especially acid (s), containing acidic species that are added to a hydrogen peroxide solution to reduce the rate of degradation.

"Acid species" refers to a substance capable of donating protons.

"Reaction mixture" refers to a mixture of olefins, hydrogen peroxide solution at a predetermined pH, catalyst and solvent. The reaction mixture may further comprise other reactants, including but not limited to cosolvents, which are discussed in more detail herein.

For embodiments, the method of epoxidizing the olefins of the present invention (also referred to as the "epoxidation method") involves the reaction of olefins (where olefins are not propylene) and hydrogen peroxide solution at a predetermined pH in the presence of a catalyst and a solvent. Reacting at temperature. For embodiments, the pH of the hydrogen peroxide solution is adjusted to the desired pH by contacting the hydrogen peroxide solution with a supported base to remove acidic species from the hydrogen peroxide solution. The process of the present invention provides for the epoxidation of olefins without reducing hydrogen peroxide utilization or hydrogen peroxide conversion compared to epoxidation of olefins without using a supported base to adjust the pH of the hydrogen peroxide solution to a predetermined pH. Increases selectivity

For embodiments, the epoxidation method includes reacting hydrogen peroxide with olefins. Hydrogen peroxide is present in aqueous solution, referred to as hydrogen peroxide solution, where hydrogen peroxide in the hydrogen peroxide solution reacts with the olefin to produce epoxides. The hydrogen peroxide solution may further contain other materials that may or may not participate in the epoxidation process to form epoxides. For example, acidic species may be present in the hydrogen peroxide solution, which is described in more detail herein.

For embodiments, the olefins used in the process may be selected from the group consisting of straight and / or branched bicyclic or cyclic aliphatic or aromatic olefins, including those that may contain multiple double bonds, provided that the olefin Is not propylene. For the embodiment, the olefin is preferably allyl chloride. Further examples of olefins are chloride-butadiene and other straight chain alkenes, cyclohexenes and other cyclic alkenes and diallkenes, substituted alkenes such as halogenated alkenes, styrene, divinylbenzene, dicyclopentadiene, Other aromatic alkenes and mixtures thereof, including but not limited to. In addition, butene, pentene, hexene, octenhepten-1,1-tridecene, mesityl oxide, isoprene, cyclooctane, cyclohexene or bicyclic compounds such as norbornene or pinene can also be used in the process. have.

For embodiments, the amount of olefins used in the reaction mixture is in the range of 10 wt% (wt%) to 90 wt%, more preferably in the range of 30 wt% to 70 wt%, based on the total weight of the reaction mixture. Preferably it may be in the range of 40wt% to 65wt%.

For embodiments, the epoxidation method comprises reacting olefins with hydrogen peroxide, where hydrogen peroxide is present in the hydrogen peroxide solution. However, as will be appreciated by those skilled in the art, other organic and / or inorganic hydroperoxides may be used for the epoxidation of olefins. Examples of other hydroperoxides that may be used include tert-butyl hydroperoxide, ethylbenzene hydroperoxide, acetyl peroxide, benzoyl peroxide, methyl ethyl ketone peroxide, cumene peroxide, and combinations thereof This is not restrictive. For embodiments, the amount of hydrogen peroxide solution used in the reaction mixture is in the range of 1 wt% to 35 wt%, more preferably in the range of 1 wt% to 15 wt%, even more preferably 1 wt, based on the total weight of the reaction mixture. It may be in the range of% to 7wt%.

Available sources of hydrogen peroxide solution are produced by hydrolysis of persulfuric acid, more typically by continuous hydrogenation and oxidation of substituted alkylanthroginones in a suitable solvent system. Both methods produce a hydrogen peroxide solution that can contain high levels of impurities such as solids and transition metal ions introduced during the preparation of the hydrogen peroxide solution. Even hydrogen peroxide solutions with very small amounts of impurities tend to decompose during storage and / or use. Thus, stabilizers containing acidic species are added to the hydrogen peroxide solution to reduce and / or prevent degradation. Examples of stabilizers may include phosphoric acid, nitric acid, tin, tartarate, organic phosphate or mixtures thereof.

For embodiments, the epoxidation method includes adjusting the pH of the hydrogen peroxide solution to a predetermined pH prior to reacting the hydrogen peroxide solution with the olefin. The pH of the hydrogen peroxide solution is adjusted by contacting the hydrogen peroxide solution with a supported base. The supported base is selected from supported bases which predominantly have a neutral charge and do not participate in ion exchange. That is, the supported base may accept or donate ions, but not both, in exchange for another ion. For embodiments, the supported base can act like a "destabilizer" and reduce the acidic species and metals that may be present from the preparation of the hydrogen peroxide solution. Supported bases can reduce the acidic species present in the hydrogen peroxide solution by accepting ions, but instead donating ions. More specifically, the supported base can accept protons. By accepting protons, the pH of the hydrogen peroxide solution is adjusted to a predetermined pH while the prevailing neutral charge of the supported base changes to a positive charge.

For an embodiment, the amount of supported base required to adjust the pH of the hydrogen peroxide solution to the desired pH will depend on the amount of hydrogen peroxide solution used in the reaction mixture and the predetermined pH value. Thus, sufficient supported base is used until the desired pH of the hydrogen peroxide solution is achieved. For an embodiment, the predetermined pH may be in the range 1.0-9.0, more preferably in the range 3.0-7.0, even more preferably in the range 4.0-6.0, most preferably in the range 5.0-5.5.

As discussed herein, the epoxidation process of the present invention may reduce the amount of by-products formed during the epoxidation of olefins. Epoxidation of olefins such as allyl chloride may include water, 1-chloro-3-methoxy-2-propanol (CMP), 1-chloro-2,3-propanediol (MCH) and high molecular weight by-products. To produce byproducts. Such byproducts may be formed by stabilizers present in the hydrogen peroxide solution. For example, acidic species in the stabilizer may catalyze the ring opening reaction during the formation of the epoxide. This ring opening reaction can produce high molecular weight by-products and some of CMP and MCH by-products. Thus, reducing the acidic species in the hydrogen peroxide solution limits the ring opening reaction and reduces the amount of by-products formed during epoxidation. By limiting the ring-opening reaction, the selectivity of epoxidation of olefins is increased and more epoxide is produced during epoxidation. For embodiments of the present invention, an increase in selectivity is achieved without reducing hydrogen peroxide utilization or hydrogen peroxide conversion compared to epoxidation of olefins without using a supported base to adjust the pH of the hydrogen peroxide solution to a predetermined pH. Is achieved.

For embodiments, the pH of the hydrogen peroxide solution is adjusted to the desired pH by contacting the hydrogen peroxide solution with a supported base. Contacting the hydrogen peroxide solution with the supported base can be carried out in batch or continuous mode. For example, the hydrogen peroxide solution can be mixed with a supported base to form a heterogeneous solution, or the hydrogen peroxide solution can be passed through a fixed bed reactor containing the supported base. For embodiments, mixing the hydrogen peroxide solution with the supported base can be carried out by known mixing means, such as, but not limited to, stirring with a stirrer, or by inducing shear forces from the tubular reactor or loop reactor to the mixing element. . It is also possible to use a combination of reactors to contact the hydrogen peroxide solution with a supported base.

For embodiments, the epoxidation of the olefins is carried out in the presence of a catalyst. In addition, one or more catalysts may be used in the epoxidation process. The catalyst used in the process may be selected from heterogeneous catalysts including porous oxide materials such as zeolites. As will be appreciated, zeolites are solids containing silica with microporous crystalline ordered channels with cage structures and pore openings. In addition to microporous zeolites, mesoporous and macroporous zeolite type catalysts may also be used. For the embodiment, the catalyst is preferably selected from titanium-silicalite which is generally known as TS-1 having an MFI structure. It is also possible to use titanium-silicalite having a MEL or intermediate MFI / MEL structure and titanium-silicalite from a beta zeolite having a BEA structure and containing titanium. Other titanium containing zeolite catalysts generally known as TS-2, TS-3, ZSM-48 and ZMS-12 can also be used.

For embodiments, some or all of the titanium in the zeolite catalyst can be replaced with, but not limited to, boron, aluminum, iron, gallium, vanadium, zirconium, chromium, niobium or mixtures of two or more thereof. Further examples of zeolites containing titanium, vanadium, chromium, niobium and zirconium are BEA, MOR, TON, MTW, FER, CHA, ERI, RHO, GIS, BOG, NON, EMT, HEU, KFI, FAU, DDR, Including, but not limited to, MTT, RUT, RTH, LTL, MAX, GME, NES, OFF, SGT, EUO, MFS, MWW, and ITQ-4. It is also possible to use titanium-containing zeolites having UTD-1, CIT-1 or CIT-5 structures in the process of the invention. In addition, other heterogeneous and homogeneous catalysts may be used. Examples include, but are not limited to, soluble metal catalysts such as ligand-bound rhenium, tungsten and manganese and their heterogeneous forms.

For embodiments, the catalyst is in the range of 0.1 wt% to 30 wt%, more preferably in the range of 0.1 wt% to 15 wt%, even more preferably 0.1 wt% to 5 wt%, based on the total weight of the reaction mixture. Can be used within the range.

The catalyst used for epoxidation will eventually be deactivated. Once the catalyst is deactivated, the deactivated catalyst can be separated and regenerated and reused for subsequent epoxidation processes. Formation of byproducts, especially high molecular weight byproducts, can increase the rate of inactivation by blocking the pores of the catalyst. As provided herein, the epoxidation process of the present invention helps to minimize the amount of by-products formed. Minimizing the by-products can reduce the rate at which the pores of the catalyst are blocked. Reducing the rate at which the pores of the catalyst become clogged can increase the lifetime of the catalyst as compared to epoxidation of olefins without using a supported base to adjust the pH of the hydrogen peroxide solution to a predetermined pH. For embodiments, increasing the life of the catalyst and reducing the frequency at which the catalyst must be separated and regenerated can save the cost and time associated with the epoxidation process.

For embodiments, the epoxidation process is carried out in the presence of a solvent. The solvent may be selected from protic solvents. For example, ketones such as acetone, methyl ethyl ketone and acetophenone can be used together with alcohols such as methanol, ethanol, isopropyl alcohol, tert-butyl alcohol and cyclohexanol. For the embodiment, the solvent is preferably methanol. The solvent may also be selected from ethers, hydro-alcohol mixtures, aliphatic and aromatic hydrocarbons, halogenated hydrocarbons and esters. Mixtures of various solvents may also be used. For embodiments, the amount of solvent in the reaction mixture is, based on the total weight of the reaction mixture, in the range of 3 wt% to 90 wt%, more preferably in the range of 3 wt% to 50 wt%, even more preferably 3 wt% to 10 wt%. It can be in the% range.

For embodiments, the epoxidation process can be performed in the presence of a cosolvent. Cosolvents are selected from non-aqueous solvents including, but not limited to, straight and cyclic C ₃ -C ₁₈ alkanes, halogenated hydrocarbons, inactivated aromatics, amides, solvents containing nitriles, alcohols and halogenated alcohols or mixtures thereof Can be. Examples of cosolvents are carbon tetrachloride, propyl chloride, chloroform, dichloromethane, dichloroethane, hexane, octane, decalin, perfluorodecalin, mono or poly-chlorinated benzene, mono- or poly-brominated benzene, acetophenone, benzonitrile, Acetonitrile, trichlorotrifluoroethane, trichloroethanol, trifluoroethanol or mixtures thereof, but is not limited thereto. For the embodiment, the cosolvent is preferably 1,2-dichlorobenzene. The cosolvent may be used in the range of 5 wt% to 70 wt%, more preferably in the range of 10 wt% to 50 wt%, even more preferably in the range of 10 wt% to 30 wt%.

For embodiments, the epoxidation process is carried out at the desired reaction temperature. For embodiments, the predetermined reaction temperature may be in the range of 0 ° C to 100 ° C, more preferably in the range of 10 ° C to 80 ° C, even more preferably in the range of 40 ° C to 60 ° C. In addition, the desired reaction temperature can be maintained at a constant temperature during the epoxidation of the olefin. For embodiments, epoxidation of the olefins is carried out at one standard arm (101.3 kilopascal), although other pressures may be used. In addition, the pressure can be changed during epoxidation.

For embodiments, the epoxidation process can be carried out in a continuous, semicontinuous or batch process. The epoxidation process can also be carried out in at least one batch reactor or at least one continuous reactor or a combination thereof. For example, the reactor may be selected from, but not limited to, one or more continuous stirred tank reactors, tubular reactors, or combinations thereof. The reactor can also be selected from a liquid-liquid contactor such as Karr Column.

For embodiments, a hydrogen peroxide solution at a predetermined pH is added to a pre-reaction solution comprising olefins, catalyst, solvent and cosolvent (if one is used) to form a reaction mixture. Hydrogen peroxide solution at a predetermined pH can be added to form a reaction mixture with or without a supported base. In some cases, the supported base may be removed from the hydrogen peroxide solution by standard separation procedures such as, but not limited to, vacuum filtration.

For embodiments, a substantial portion of the resulting epoxide will be formed in the organic phase, which may include some of the unreacted olefins, cosolvents and by-products. However, some of the resulting epoxide may remain in the aqueous phase, which may include some of the unreacted hydrogen peroxide, solvents and by-products. Thus, the organic and aqueous phases can be separated from the base (if not already removed) and catalyst supported by conventional separation techniques such as decantation, hydrocyclone, mechanically driven high gravity devices or combinations thereof. have. The resulting epoxide can also be separated and / or recovered from the organic and aqueous phases using techniques such as but not limited to distillation.

Example

The following examples are provided to illustrate the invention but do not limit the scope thereof.

material

Hydrogen peroxide solution (30 wt% aqueous solution), available from VWR.

Olefin, Allyl Chloride (99.4% Purity), Freeport Commercially available from B6800 Block Allyl Chloride Plant. Olefin, allyl chloride is also available from Sigma Aldrich (Reagent Plus, 99%, CAS # 107-05-1).

Solvent, Methanol (99.8%, approved ACS, CAS # 67-56-1), commercially available from Fisher Scientific.

Cosolvent, 1,2-dichlorobenzene (Reagent Plus, 99%, CAS # 95-50-1), commercially available from Sigma Aldrich.

Catalyst, titanium-silicalite (TS-1, titanium content is approximately 2.1 wt%), commercially available from Sud-Chemie.

Supported base, poly-4-vinylpyridine (CAS # 25232-41-1), commercially available from Sigma Aldrich.

Supported base, Amberlyst® A-21 (free base, 20-5-mesh, CAS # 9049-93-8), commercially available from Sigma Aldrich.

Supported base, Lewatit® MP-62 (free base, 300-1000 micrometers (μm)), commercially available from Sigma Aldrich.

Supported base, Dowex® MWA-1 (free base, 53-75 mesh, CAS # 63993-97-9), commercially available from Sigma Aldrich.

Ion exchange resin, Amberlyst® A-26 (hydroxide form, 16-45 mesh, CAS # 39339-85-0), commercially available from Sigma Aldrich.

Ion exchange resin, silica-supported trimethylpropyl aluminum carbonate (0.8 mmol / gram load, 200-400 mesh), commercially available from Sigma Aldrich.

Ion exchange resin, Reillex® HPQ (partially quaternized methyl chloride salt, 300-1000 μm particle size, CAS # 125200-80-8), commercially available from Sigma Aldrich,

Homogeneous ionic base, sodium hydroxide (reagent grade, ≥ 98%, CAS # 1310-73-2), commercially available from Sigma Aldrich.

Test Methods

pH Measurement of

pH was measured with a Beckman model 45 pH meter using an Orion 8272BN composite electrode with 3M potassium chloride (KCl) fill solution. Beckman was calibrated daily with pH = 4 and pH = 7 buffers.

Gas chromatography

Gas chromatography (GC) was performed with an HP 6890 series G1530A GC with a JP 7682 series injector and flame ionization detector.

proper

The amount of hydrogen peroxide was analyzed by iodine titration using 0.01 N sodium thiosulfate. The hydrogen peroxide concentration was calculated as follows: parts per million (ppm) hydrogen peroxide = (milliliters (ml) of titrant used)) (0.01 N) (17000) / g sample. Titration was performed using a Mettler Toledo DL5x V2.3 titrator with DM 140 sensor.

Example  One : Supported  Of allyl chloride using hydrogen peroxide solution with base Epoxidation

52.3 wt% allyl chloride, 5 wt% methanol, 23.3 wt% 1,2-dichlorobenzene, and 1.4 wt% TS-1 catalyst with stainless steel cooling coil, thermocouple, mechanical stirrer, addition funnel, nitrogen purge and reflux condenser with gas scrubber The pre-reaction solution was added to a 750 ml jacketed glass reactor equipped with a cold finger combination, where the weight percentages were based on the total weight of the reaction mixture. The pre-reaction solution was heated to 25.5 ° C.

The hydrogen peroxide solution was stirred with sufficient Amberlyst® A-21 to adjust the pH of the hydrogen peroxide solution to the desired pH 5.7. The amount of hydrogen peroxide solution stirred with Amberlyst® A-21 was 18 wt% of the total reaction mixture. A mixture of hydrogen peroxide solution and Amberlyst® A-21 was added to the addition funnel. The hydrogen peroxide solution and Amberlyst® A-21 mixture were slowly added to the reactor containing the pre-reaction solution to form the reaction mixture. The reaction mixture was heated to a predetermined reaction temperature of 40 ° C. +/− 0.5 ° C. for 60 minutes with stirring at 600 revolutions per minute. The contents of the reactor were collected from the reactor in two 250 milliliter (ml) centrifuge tubes and centrifuged for 30 minutes at 0 ° C. at 3000 rpm. The aqueous and organic phases were decanted into separate funnels. Both phases were analyzed by gas chromatography. The remaining hydrogen peroxide was determined by titration with sodium thiosulfate. The results of Example 1 and the following Examples 2 to 10 are illustrated in Table 1.

Example  2: Supported  Epoxidation of Allyl Chloride with Hydrogen Peroxide Solution with Base

The procedure of Example 1 was repeated but changed as follows. The hydrogen peroxide solution was stirred with sufficient poly-4-vinylpyridine to adjust the pH of the hydrogen peroxide solution to the desired pH 5.

Example  3: Supported  Epoxidation of Allyl Chloride with Hydrogen Peroxide Solution with Base

The procedure of Example 1 was repeated but changed as follows. The hydrogen peroxide solution was stirred with sufficient Lewatit® MP-62 to adjust the pH of the hydrogen peroxide solution to the desired pH 5.2.

Example  4: Supported  Epoxidation of Allyl Chloride with Hydrogen Peroxide Solution with Base

The procedure of Example 1 was repeated but changed as follows. The hydrogen peroxide solution was stirred with sufficient Dowex® MWA-1 to adjust the pH of the hydrogen peroxide solution to the desired pH 5.2.

Example  5: Supported  Epoxidation of Allyl Chloride with Hydrogen Peroxide Solution with Base

The procedure of Example 1 was repeated but changed as follows. The hydrogen peroxide solution was stirred with sufficient poly-4-vinylpyridine to adjust the pH of the hydrogen peroxide solution to the desired pH 4.5.

Example  6: Supported  Epoxidation of Allyl Chloride with Hydrogen Peroxide Solution with Base

The procedure of Example 1 was repeated but changed as follows. The hydrogen peroxide solution was stirred with Amberlyst® A-21 to adjust the pH of the hydrogen peroxide solution to the desired pH 4.6.

Example  7: Supported  Epoxidation of Allyl Chloride with Hydrogen Peroxide Solution with Base

The procedure of Example 1 was repeated but changed as follows. The pH of the hydrogen peroxide solution was adjusted to a predetermined pH 5.5. Amberlyst® A-21 was separated from the hydrogen peroxide solution using vacuum filtration. The addition funnel was charged with a filtered hydrogen peroxide solution (ie filtrate). The filtered hydrogen peroxide solution was then slowly added to the reactor containing the pre-reaction solution.

Example  8: Supported  Using a hydrogen peroxide solution with base and reusing the catalyst Allyl chloride Epoxidation

The procedure of Example 7 was repeated but changed as follows. Instead of using fresh TS-1 for the catalyst, the separated catalyst from Example 7 was reused. Prior to vacuum filtration, the pH of the hydrogen peroxide solution was adjusted to the desired pH 5.6.

Example  9: Supported  Epoxidation of Allyl Chloride with Hydrogen Peroxide Solution with Base

The procedure of Example 7 was repeated but changed as follows. The hydrogen peroxide solution was stirred with sufficient poly-4-vinylpyridine to adjust the pH of the hydrogen peroxide solution to the desired pH 5.6 before vacuum filtration.

Example  10: Supported  Use a hydrogen peroxide solution with base and catalyst Reused  Allyl chloride Epoxidation

The process of Example 8 was repeated but changed as follows. Instead of using fresh TS-1 catalyst, the separated TS-1 catalyst from Example 9 was reused. The hydrogen peroxide solution was stirred with sufficient poly-4-vinylpyridine to adjust the pH of the hydrogen peroxide solution to the desired pH 5.4 before vacuum filtration.

compare Example

The following is a comparative example. Comparative Examples A to E adjust the pH of the hydrogen peroxide solution with an ion exchange resin and a homogeneous ionic base. Comparative Examples F and G do not use any form of pH adjustment or control. The results of the comparative examples are illustrated in Tables 2 and 3.

compare Example  A: of allyl chloride using a hydrogen peroxide solution having an ion exchange resin Epoxidation

The procedure from Example 1 was repeated but changed as follows. The hydrogen peroxide solution was stirred with sufficient Amberlyst® A-26 to adjust the pH of the hydrogen peroxide solution to 5.5.

compare Example  B: of allyl chloride using hydrogen peroxide solution with ion exchange resin Epoxidation

The procedure from Example 1 was repeated but changed as follows. The hydrogen peroxide solution was stirred with sufficient silica-supported trimethylpropyl ammonium carbonate to adjust the pH of the hydrogen peroxide solution to 5.02.

compare Example  C: of allyl chloride using hydrogen peroxide solution with ion exchange resin Epoxidation

The procedure from Example 1 was repeated but changed as follows. The hydrogen peroxide solution was stirred with sufficient Reillex® HPQ to adjust the pH of the hydrogen peroxide solution to 5.5.

compare Example  D: Homogeneous  Of allyl chloride using hydrogen peroxide solution with ionic base Epoxidation

The procedure from Example 1 was repeated but changed as follows. The pH of the hydrogen peroxide solution was adjusted to 5.6 by mixing the hydrogen peroxide solution with a sufficient aqueous sodium hydroxide solution.

compare Example  E: of allyl chloride using a hydrogen peroxide solution with a homogeneous ionic base Epoxidation

The procedure from Example 1 was repeated but changed as follows. The initial pH of the hydrogen peroxide solution was adjusted to 6.2 by mixing the hydrogen peroxide solution with a sufficient aqueous sodium hydroxide solution. Sodium hydroxide solution was added periodically throughout the reaction to maintain a pH above 5.0.

compare Example  F: any form pH  Of allyl chloride using hydrogen peroxide solution without control or control Epoxidation

The procedure from Example 1 was repeated but changed as follows. The pH of the hydrogen peroxide solution was not adjusted. Therefore, nothing was done to the hydrogen peroxide solution to adjust the pH.

compare Example  G: some form pH  Of allyl chloride using a hydrogen peroxide solution with no control or control and reusing the catalyst Epoxidation

The procedure from Comparative Example F was repeated but changed as follows. Instead of using fresh TS-1 catalyst, the separated TS-1 catalyst from Comparative Example F was reused.

Table 1 is a summary of the examples, and Tables 2 and 3 are summary of the comparative examples. In the table, "CMP" represents 1-chloro, 3-methoxy, 2-propanol, "MCH" represents 1-chloro-2,3-propanediol (monochlorohydrin), and "epi" is epi Chlorohydrin is shown.

"Hydrogen peroxide conversion" is calculated as (total amount of hydrogen peroxide reacted during epoxidation) / (amount of hydrogen peroxide added to the reaction mixture), and "hydrogen peroxide utilization" is (amount of hydrogen peroxide converted to epi) / (epoxidation) Amount of hydrogen peroxide reacted for a while). "Selectivity" is (amount of epi formed) / (ep formed + amount of all byproducts). Selectivity is illustrated in Table 1 as the amount of each byproduct formed.

One factor in the epoxidation of olefins is the pH of the reaction mixture. Thus, when comparing an example with a comparative example, it is most effective to compare those at approximately the same pH. Therefore, Examples 1-4 are compared with Comparative Examples A-D, and Examples 5 and 6 are compared with Comparative Examples F and G. In addition, since hydrogen peroxide is the most expensive reagent used in the epoxidation process, those skilled in the art understand that a few percent difference in hydrogen peroxide utilization makes a significant difference in financial savings.

The comparison between Table 1 and Table 2 shows the benefits of using a supported base to adjust the hydrogen peroxide solution to the desired pH (Examples 1-4) versus ion exchange resins (Comparative Examples A-C) or homogeneous ions. The advantage of using a sex base (comparative example D) is illustrated. As can be seen in Table 1, Examples 1-4 maintain high selectivity, evidenced by the lower amount of by-products formed without reducing hydrogen peroxide conversion or hydrogen peroxide utilization. Comparative Examples A-D illustrated in Table 2 show that the hydrogen peroxide conversion is relatively high, but the amount of hydrogen peroxide converted to epoxide is significantly reduced, which is expressed as hydrogen peroxide utilization.

The benefits of pH control (Examples 5 and 6 in Table 1) versus pH uncontrolled (Comparative Examples F and Comparative Example G in Table 3) have been found in the amount of CMP, MCH and high molecular weight by-products formed during epoxidation. This is evidenced by a significant reduction in. Comparative Examples F and G, without adjusting the pH, demonstrate reduced selectivity. The reduced selectivity of Comparative Examples F and G can be seen as a significant increase in the amount of CMP, MCH and polymer by-products compared to Examples 5 and 6 using pH control.

1 shows the amount of epi formed throughout the epoxidation process of allyl chloride. 1 compares Examples 7-10 with Comparative Examples F and G. FIG. As can be seen in FIG. 1, when the pH of the hydrogen peroxide solution is adjusted with a supported base Amberlyst® A-21 (Example 7) or poly-4-vinylpyridine (Example 9), the catalyst is reused (Example Example 8 and Example 10) The long term efficacy of the catalyst is not reduced.

Claims (11)

As an epoxidation method of an olefin, the method
Reacting an olefin (where the olefin is not propylene) with a hydrogen peroxide solution at a predetermined pH at a predetermined reaction temperature in the presence of a catalyst and a solvent, wherein the pH of the hydrogen peroxide solution is reacted with a supported base Contact to remove the acidic species from the hydrogen peroxide solution to adjust to a predetermined pH, and the selectivity of epoxidation of the olefin is such that the olefin does not use the supported base to adjust the pH of the hydrogen peroxide solution to the desired pH. A process for epoxidation of olefins without increasing hydrogen peroxide utilization or hydrogen peroxide conversion compared to epoxidation of olefins. The method of claim 1, wherein the olefin and the hydrogen peroxide solution at the predetermined pH are reacted in the presence of a cosolvent. The method of claim 1, wherein the hydrogen peroxide solution comprises a stabilizer and the pH of the hydrogen peroxide solution is adjusted to a predetermined pH when the acidic species is removed from the stabilizer. The method of claim 1, wherein the acidic species comprises ions and the supported base receives ions but does not donate ions to the hydrogen peroxide solution. The method of claim 1, wherein the supported base predominantly has a neutral charge before adjusting the pH of the hydrogen peroxide solution. 6. The method of claim 1, wherein the supported base acquires a positive charge when adjusting the pH of the hydrogen peroxide solution to the predetermined pH. 7. The method according to any one of claims 1 to 6, wherein the predetermined reaction temperature is maintained during the epoxidation reaction. The method of claim 1, wherein the olefin is allyl chloride and the epoxidation produces epichlorohydrin. 9. The method of claim 1, wherein the predetermined pH is in the range of 1.0 to 9.0. 10. The method according to claim 1, wherein the predetermined pH is in the range of 5.0 to 5.5. An epoxide obtainable by the method according to any one of claims 1 to 10.

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